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How to Check Ammonia Level in RV Refrigerator: 4 Methods

how to check ammonia level in rv refrigerator

Whether it’s an RV from a few decades ago or a modern model that came out this year, a refrigerator is always included as one of the essential features.

You won’t have a perfect RV journey without a reliable refrigerator. Without it, you can only take with you a few kilos of beef jerky and canned goods.

Most portable refrigerators, including those in RVs, operate with ammonia-based coolants instead of HFCs or CFCs. But leaked ammonia can pose a health hazard.

Therefore, it is essential to know how to check ammonia level in RV refrigerator before every trip. Today, we will cover four different methods to help you do just that.

  • Way 1: Utilize Your Senses
  • Way 2: Use Ammonia Detector
  • Way 3: Use Phenolphthalein Test Strip
  • Way 4: Utilize Sulfur Stick

Keep reading to see more!

4 Ways to Check Ammonia Level in RV Refrigerator


Way 1: Utilize Your Senses

It is okay to use your ears and nose to check for ammonia leaks. But, of course, this method will not be as accurate and reliable as the others listed here.

Detailed Guide

  • Step 1: Check Out the Smell inside the Box

The good news is that the smell of ammonia is very strong and specific, allowing you to identify it easily.

So, if you want to check manually, start by sniffing the inside of the box. If you notice a strong ammonia smell, the evaporator region may be leaking.

The strong smell of ammonia may disappear if your appliance has been leaking for a while. That’s when your hearing comes into play. After a few minutes of your refrigerator turning on, it may make a gurgling sound.

  • Step 2: Check Out Heat

The coils must be heated to allow the coolant to properly run through the tubes and enable your refrigerator to function correctly.

Hence, uneven heat in the coils can signify not having enough coolant flowing through the tubes. The most obvious sign is that certain parts of coils will get extremely hot.

Way 2: Use Ammonia Detector


Using an ammonia detector is the most effective and reliable solution for checking the ammonia level in your RV refrigerator. It will show you exactly how much ammonia is leaking.

What You Need to Prepare

All you need to prepare is an ammonia detector.

If your refrigerator has an ammonia leak, it will indicate the exact extent of the leak. These devices also come with vibration and audible or visual alarm settings to alert that your refrigerator is leaking ammonia.

Detailed Guide

  • Step 1: Set Up Your Ammonia Detector

Setting your detector up in an ideal spot will allow it to detect leaks as soon as possible.

Ammonia is lighter than air and tends to rise upwards. As such, we recommend installing your ammonia detector near a ceiling, where it is close to a gas source and with good airflow.

Also, you should keep it away from exhaust fans. In most cases, it’s wise to place your detector on the refrigerator’s compressor. It is okay to install it 5 feet above the floor and within 30 feet of your refrigerator.

  • Step 2: Pay Attention to The Signs

Your ammonia detector may sound an alarm or light up to let you know that there is a large amount of ammonia in the air, which could be leaking from your RV refrigerator.

Once your detector detects ammonia, your refrigerator’s coolant level drops. In this case, you will need to get expert help in RV fridge ammonia leak repair as soon as possible.

Way 3: Use Phenolphthalein Test Paper


If you want to save money and don’t want to invest in an ammonia detector, you can use a phenolphthalein test strip to identify ammonia leaks. However, it is not a quantitative method.

What You Need to Prepare

  • Phenolphthalein Test Strip

When exposed to ammonia in the air, phenolphthalein paper will turn from white to pink. So, you can use them to detect ammonia leakage.

  • Water

Phenolphthalein paper only works for solutions. Therefore, you will need water to moisten it.

Detailed Guide

  • Step 1: Wet Your Phenolphthalein Test Strip

Start by carefully removing a phenolphthalein test strip from its jar with your fingertips. You need to avoid touching the rest of the test strips.

Next, wet this test strip by dipping it in a beaker of distilled water so that the ammonia gas can penetrate it; ensure that you do not over-soak it.

It is okay to use any type of water. However, we recommend distilled water as it is free of impurities, which may otherwise change the color of the paper.

  • Step 2: Move It Around

Grab your phenolphthalein test strip with two fingertips and move it around the RV refrigerator. Then, get close to the compressor and inside the box.

Since ammonia is lighter than air, you also need to move the test strip closer to the ceiling, where there is good airflow.

If your phenolphthalein paper turns fuchsia or pink, your refrigerator is leaking ammonia, and you will need to get help in RV fridge repair from an expert.

Conversely, if it doesn’t change color, there’s no ammonia leaking, and you can start your journey with peace of mind.

Way 4: Utilize Sulfur Stick


This is essentially the same as using a phenolphthalein test strip. It works well, but you’ll need to be careful when handling the burning stick.

What You Need to Prepare

  • Sulfur Stick

It is made from a wick containing sulfur particles, which can light up when in contact with little ammonia. These sticks are usually stored in a sealed tube.

  • Matchstick or Lighter

You will need to light your sulfur stick for it to work. You can use a lighter or a match, as long as this stick is lit correctly.

Detailed Guide

  • Step 1: Light Your Sulfur Stick

Take a sulfur stick and hold the end opposite the wick with your fingertips. Then, light the wick with a lighter or match. If the wick is lit correctly, it will smolder like the smoldering stick utilized for fireworks.

We recommend using a match as it is more environmentally friendly than a lighter and easier to use. The lighter will give you a quick light, but it can’t work properly in cold weather.

If you use a lighter, you can hold the sulfur stick in one hand and use the other hand to hold the lighter. On the other hand, if you decide to go with a match, you’ll need to ask a friend to help you light your sulfur stick.

  • Step 2: Move Sulfur Stick Around

Once you have lit the sulfur stick, move it the same way you would with the phenolphthalein test strip.

If your refrigerator has an ammonia leak, your sulfur stick will start to give off white smoke. In this case, you will need a call to a trusted specialist for ammonia refrigerator repair.

If nothing out of the ordinary happens to the sulfur stick, your refrigerator is not leaking.

Why Use Ammonia for RV Refrigerators?

Although no longer common, some refrigerator manufacturers use ammonia for small refrigerators and portable refrigerators for RVs.

One of the main reasons ammonia is used in RV refrigerators is its strong odor, allowing you to detect an ammonia leak quickly.

What Are Pros and Cons of Using Ammonia for RV Refrigerators?



  • Inexpensive
  • Energy-efficient


  • Corrosive
  • Slightly Toxic
  • Flammable

The Bottom Line

An RV refrigerator is one of the most critical devices in your vehicle, especially on long journeys. It allows you to enjoy fresh foods anytime and anywhere.

Most RV refrigerators operate on ammonia-based coolants. That’s why you need to know how to check ammonia level in RV refrigerator.

When you start to notice a slight ammonia smell from your refrigerator, it is essential to repair it as soon as possible.

Thank you for reading!

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